package org.bouncycastle.asn1.pkcs;

import java.math.BigInteger;
import java.util.Enumeration;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.DERInteger;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERSequence;

public class RSAPrivateKeyStructure extends ASN1Encodable {
    private int version;
    private BigInteger modulus;
    private BigInteger publicExponent;
    private BigInteger privateExponent;
    private BigInteger prime1;
    private BigInteger prime2;
    private BigInteger exponent1;
    private BigInteger exponent2;
    private BigInteger coefficient;
    private ASN1Sequence otherPrimeInfos = null;

    public static RSAPrivateKeyStructure getInstance(ASN1TaggedObject obj,
            boolean explicit) {
        return getInstance(ASN1Sequence.getInstance(obj, explicit));
    }

    public static RSAPrivateKeyStructure getInstance(Object obj) {
        if (obj instanceof RSAPrivateKeyStructure) {
            return (RSAPrivateKeyStructure) obj;
        } else if (obj instanceof ASN1Sequence) {
            return new RSAPrivateKeyStructure((ASN1Sequence) obj);
        }

        throw new IllegalArgumentException("unknown object in factory: "
                + obj.getClass().getName());
    }

    public RSAPrivateKeyStructure(BigInteger modulus,
            BigInteger publicExponent, BigInteger privateExponent,
            BigInteger prime1, BigInteger prime2, BigInteger exponent1,
            BigInteger exponent2, BigInteger coefficient) {
        this.version = 0;
        this.modulus = modulus;
        this.publicExponent = publicExponent;
        this.privateExponent = privateExponent;
        this.prime1 = prime1;
        this.prime2 = prime2;
        this.exponent1 = exponent1;
        this.exponent2 = exponent2;
        this.coefficient = coefficient;
    }

    @SuppressWarnings("rawtypes")
    public RSAPrivateKeyStructure(ASN1Sequence seq) {
        Enumeration e = seq.getObjects();

        BigInteger v = ((DERInteger) e.nextElement()).getValue();
        if (v.intValue() != 0 && v.intValue() != 1) {
            throw new IllegalArgumentException(
                    "wrong version for RSA private key");
        }

        version = v.intValue();
        modulus = ((DERInteger) e.nextElement()).getValue();
        publicExponent = ((DERInteger) e.nextElement()).getValue();
        privateExponent = ((DERInteger) e.nextElement()).getValue();
        prime1 = ((DERInteger) e.nextElement()).getValue();
        prime2 = ((DERInteger) e.nextElement()).getValue();
        exponent1 = ((DERInteger) e.nextElement()).getValue();
        exponent2 = ((DERInteger) e.nextElement()).getValue();
        coefficient = ((DERInteger) e.nextElement()).getValue();

        if (e.hasMoreElements()) {
            otherPrimeInfos = (ASN1Sequence) e.nextElement();
        }
    }

    public int getVersion() {
        return version;
    }

    public BigInteger getModulus() {
        return modulus;
    }

    public BigInteger getPublicExponent() {
        return publicExponent;
    }

    public BigInteger getPrivateExponent() {
        return privateExponent;
    }

    public BigInteger getPrime1() {
        return prime1;
    }

    public BigInteger getPrime2() {
        return prime2;
    }

    public BigInteger getExponent1() {
        return exponent1;
    }

    public BigInteger getExponent2() {
        return exponent2;
    }

    public BigInteger getCoefficient() {
        return coefficient;
    }

    /**
     * This outputs the key in PKCS1v2 format.
     * 
     * <pre>
     *      RSAPrivateKey ::= SEQUENCE {
     *                          version Version,
     *                          modulus INTEGER, -- n
     *                          publicExponent INTEGER, -- e
     *                          privateExponent INTEGER, -- d
     *                          prime1 INTEGER, -- p
     *                          prime2 INTEGER, -- q
     *                          exponent1 INTEGER, -- d mod (p-1)
     *                          exponent2 INTEGER, -- d mod (q-1)
     *                          coefficient INTEGER, -- (inverse of q) mod p
     *                          otherPrimeInfos OtherPrimeInfos OPTIONAL
     *                      }
     * 
     *      Version ::= INTEGER { two-prime(0), multi(1) }
     *        (CONSTRAINED BY {-- version must be multi if otherPrimeInfos present --})
     * </pre>
     * <p>
     * This routine is written to output PKCS1 version 2.1, private keys.
     */
    public DERObject toASN1Object() {
        ASN1EncodableVector v = new ASN1EncodableVector();

        v.add(new DERInteger(version)); // version
        v.add(new DERInteger(getModulus()));
        v.add(new DERInteger(getPublicExponent()));
        v.add(new DERInteger(getPrivateExponent()));
        v.add(new DERInteger(getPrime1()));
        v.add(new DERInteger(getPrime2()));
        v.add(new DERInteger(getExponent1()));
        v.add(new DERInteger(getExponent2()));
        v.add(new DERInteger(getCoefficient()));

        if (otherPrimeInfos != null) {
            v.add(otherPrimeInfos);
        }

        return new DERSequence(v);
    }
}
